Implementation of complex monitoring and control processes by industrial automation systems in the chemical industries, power plants, oil refineries, and water delivery systems are typical. The industrial networks for process automation at these sites typically encompass broad areas, with highly dense networks with hundreds or thousands of nodes.
The harsh industrial environment presents several obstacles for wireless communications, the most significant of which are dependability, fault-tolerance, and low latency. Unpredictable changes in temperature, humidity, vibrations, and pressure and the presence of highly reflective (metal) items and electromagnetic noise make industrial surroundings stressful.
In these installations, thousands of devices provide measured values (such as temperature, pressure, flow, and location) to actuators that control processes and servers that coordinate the manufacturing steps. Wiring is often tricky and expensive, particularly in combustible and explosive areas (for example, in the presence of flammable gases in an oil refinery.) Remote or inaccessible places are difficult to reach, and mobile nodes can only be connected intermittently. Even though the amount of data is relatively low in an industrial application, dependability and latency are crucial, and complete data delivery in real-time is a must.
Key constraints that hinder the actual deployment of wireless networks in such settings are battery capacity and device power consumption. Communication and power wires, ideally, can be eliminated to provide a completely wireless system. To that end, the devices should be energy efficient and capable of running for years on a single charge from a battery. Furthermore, wireless networks bring logical benefits to maintenance and commissioning, such as "plug-and-play" automation systems to reduce downtime and speed up tests, as well as "hot-swapping" malfunctioning modules.
